There is such a wide variety of unique little (and big) fish out there. The more I’ve gotten to know aquariums and fish and all the other residents of these micro-ecosystems, the more amazed I am at the sheer variety and uniqueness of each species.
So many of these critters are perfectly suited for keeping at home in big, beautiful fish tanks or smaller aquariums, adding life, color, calming serenity, and so much more to our lives.
The zebra danio, in particular, is a delightful addition to the right fish tank. Their spunky little personalities, prolific breeding habits, unique bonding habits, and more make them great pets. Their hardiness and flexibility make them perfect for newbie hobbyists.
If you’re not instantly sold on them, check out the care guide below and see if these 2-inch beauties might be the perfect choice for your aquarium.
Quick Intro to Zebra Danios
|Scientific Name:||Danio rerio|
|Other Names:||Striped danio, zebra danio, zebrafish|
Natural Habitat, Identification, and Where to Buy
This little freshwater fish originates in India, Bhutan, Bangladesh, Myanmar, and Nepal – and just happens to be one of the most commonly loved aquarium fish for a number of reasons. They’re a peaceful, hardy fish species. They have silvery goldish coloration with five dark blue (almost black) stripes that extend from their heads to the caudal fins.
Their natural habitats vary from flowing streams to quiet pools.
Zebra danios have some sexual dimorphism. The males are more on the golden side, with females with a silvery-white coloration. The males also tend to be slimmer and full-bodied, while the females are rounder.
With zebra danios, there are a few species variations, including the Longfin Zebra Danio. These are selectively bred for longer fins than wild zebras danios. There are also the naturally occurring albino form. These are rare in the wild but fairly common in the fishkeeper hobby. The Golden morph form is the bred variety that has yellowish gold body with silvery white stripes.
Scientific modification (using genes from the jellyfish) have also created some glow-in-the-dark varieties known as Glo Morphs, which come in fluorescent blue, green, red, purple, and orange-yellow.
Optimal Water Conditions for Zebra Danios
|Water Temperature:||64 to 77 Fahrenheit|
|Water Flow Rate:||High flow|
|pH:||6.5 to 7.0|
|Water Hardness:||5 to 12 dGH|
|Minimum Tank Size:||10 gallon tanks|
|Optimal Tank Size:||15-20 gallons|
|Optimal Tank Shape:||Long rectangular|
|Recommended Filter Type:||HOB and other high flow rate filters|
Where zebra danios live naturally, higher temperatures abound – meaning they require fairly warm aquariums to keep them healthy and happy. You may reduce the temperature to the lower end of their ideal range during winter to keep a natural “flow” of life for them, but the temperatures should never get below about 64-degrees.
These little tropical fish come from a wide range of terrains that have low to high flow rates, but they do best in a higher flow system than slower. They’re also uses to 12+ hours of daylight from spring to summer, so should be given plenty of light.
The water in their fish tanks should be kept with pH levels between 6.0 and 8.0 and temperatures between 64 and 82 degrees, though ideally closer to between 70 and 75. They are tropical freshwater fish so prefer the warmer temperatures.
They need solid filtration to keep their water clean and clear, as well as keeping the flow rate in the tank moving pretty well. You may wish to add some air stones or even a wave maker to amp up the flow rate to a more natural feel for them.
These fish are also pretty good jumpers, so make sure you keep a lid on their aquariums to help keep them safe.
Creating the Landscape
These little fish come from habitats with silty bottomed rice paddies and lush greenery. So, ideally, when you create their landscape in your office or home aquarium, you’ll provide similar features to keep them healthy, happy, and less stressed out.
Provide them with silty substrate (particles smaller than sand, but larger than clay) or sand with some natural rocks. Add in some overhanging branch cover or floating plants. Plants live Java Fern and Amazon Swords, along with floaters like Duckweed, Red Root Floater, and Amazon Frogbit. The plants help with oxygenation, as well as providing the fish with natural shelter and hiding places.
They should also receive light approximately 12 hours per day for healthy, natural living. You may want to add some bogwood, large rounded pebbles (no jagged edges!), and some artificial caves or hiding spots.
|Best Plants:||Java fern, Amazon sword, Java moss (for spawning), Hornwort, Red Root Floater, Duckweed, Amazon Frogbit|
|Best Lighting:||Medium light for 12 hours daily|
|Best Decorations:||Live plants, rounded pebbles, bogwood, artificial caves, silty substrate or sand|
|Decorations to Avoid:||Anything with jagged edges|
Physiological Considerations for Zebra Danios
|Preferred Tank Region:||All regions|
|Scale Thickness:||Nothing of note.|
|Gill Considerations:||Nothing of note.|
|Swimbladder Considerations:||Nothing of note.|
|Fin Shape Considerations:||Nothing of note.|
When kept indoors in aquariums, these little fish grow up to 2 inches. When kept outdoor in ponds, they can get a little bigger. This probably due to having more space and “open water” as well as more natural food sources as it were.
These fish are also pretty easy to care for, as long as their fish tanks are kept clean, well filtered, and housed with proper tank companions that won’t eat them or infect them with the more common freshwater fish diseases. That also means keeping fin nippers out, as they won’t do so hot when they’ve been nibbled on. You should note that zebra danios are known to do some nipping of their own, so they shouldn’t be housed with fish with longer fins, either.
This species of small fish is a schooling fish. They have a hierarchical system of dominance among them, though it’s demonstrated through play rather than aggression – so it is safe to keep them together, and, in fact, should be kept together.
They’re a social, peaceable fish who play and chase each other around and around the tank. They may show some aggression towards slower moving, long-finned fish and may nip at their tails. Ideally, they won’t be housed with these species to avoid any negative behavior.
Because they’re a community fish, they need to be kept with zebra danios to keep them happy. They are stressed otherwise, which can lead to illness. Living without other zebra danios, they will slow down, become less active and antisocial as well, hiding away.
Large shoals, however, because them to become a bit hyperactive. This high activity may cause some species of slow moving fish anxiety and antisocial behavior, which is another good reason not to stock these little guys with those fish.
Zebra danios occupy all levels of the fish tank when they’re in shoals, though they may tend toward the middle and upper layers of the fish tank.
Ideally, you should stock 1 zebra danio per 2 gallons, with a minimum of 10 gallons as your base line. This gives the fish plenty of space to swim freely and shoal properly throughout the freshwater aquarium. This also helps prevent overstocking the tank.
Some of the best tank mates for zebra danios include:
- Other zebra danios
- Indian Flying Barb
- Honey gourami
- Emerald pufferfish
- Ember tetra
- Bengal Turquoise Danio
- Celestial pearl danio
- Burma danio
- Rosy barbs
- Rummy Nose tetras
- Bronze cory
- Dojo Loach
- Nerite snails
- African dwarf frogs
- Blue Velvet Shrimp
- Other barbs
- Other similar-sized gourami
- Yoyo loaches
- Clown loaches
- One rainbow shark or one redtail shark
Avoid keeping them with Sailfin Moll, elephant ear guppies, redtail catfish, or any other fish with fancy tails and fins.
Gender, Breeding, and Reproductive Considerations
The male and female zebra danio are pretty similar in looks, so it may be hard to sex them. However, the female is a little bit larger than the male, and a little rounder. Males have a more torpedo-shaped body, and the females have a larger belly. Both male and female have two pairs of barbels and the same stripes.
These little fish are prolific breeders – the bunny rabbits of the aquarium world – so it’s not hard to get more in that fish tank. Interestingly, mated pairs actually stay together for life and almost never spawn with others.
To create those mating pairs, start with a small school of fish with at least a half dozen young fish. They’ll choose their mates and pair off, as it were, for breeding.
For best results, set up a separate breeding tank with shallower water (about six-inches deep). Add in some fine-leafed plants for protection, and some java moss or course gravel for the eggs to fall into to protect them from the adult fish (who will eat their own eggs).
Get the water temperature up to 78-degrees or higher to trigger spawning, raising the temperature by a few degrees near dawn, when spawning occurs.
When spawning does happen, anywhere between 300 and 500 eggs will scatter around the bottom of the plants. You should be able to see the difference. When you notice the behavior changes or see the eggs, remove the breeding pair and return them to the main fish tank to prevent them from eating the eggs or the fry when they hatch.
It only takes about two days for the fry to hatch. They’re teeny tiny and get lost during water changes, so be very careful when you maintain your nursery tank. Feed the fry designated fry food. You can also add a powdered egg to their fry food to help boost growth even more.
These little fish are omnivores and in the wild mostly feeds on small crustaceans, mosquito larvae, algae, and worms. In your aquarium, many of these can be available through safely packages versions of these, including brine shrimp, algae wafers, bloodworms, and more.
The foundational foods of their diets in your aquarium should be based on high-quality, no or low-grain flakes, preferably algae based. Build on that foundation with algae wafers, bloodworms, freeze-dried brine shrimp, Daphnia, shelled peas, spinach, cucumber, and live foods. The foundational foods should be given every day, with vegetables, algae wafers, and the other supplementals given once or twice a week to boost growth and color.
|Best Sustenance Food Type:||High-quality low or no-grain algae based flakes|
|Additional Food For Optimal Health:||Freeze-dried protein like brine shrimp and bloodworms, Daphnia, and algae wafers|
|Special Foods and Considerations for Best Color and Growth:||Shrimp pellets, Daphnia, cucumber, zucchini, wingless fruit flies, shelled peas, freeze-dried brine shrimp, frozen brine shrimp, bloodworms, blackworms – any/all should be given once or twice a week minimum|
|When and How Often to Feed Fish Based on Life Cycle:||Rotate their food daily (supplements alternating along with that foundation of flakes daily), feeding them only what they can consume in under 2 minutes, once or twice daily.|
Common Diseases and How to Avoid and Treat Them
Zebras are generally a healthy, hardy fish, so they don’t get ill often. They can, however, get some of the common freshwater fish diseases like ich if the fish tank is properly kept. For the sake of all your fish and plants, maintaining the proper pH, hardness, and other parameters is important. It’s also vital to keep ammonia, nitrates, and nitrites down.
Sudden changes can also cause health issues for your fish, due to stress, so make sure you ease them into any new changes.
The other potential issue zebras might have is the bacterial infection called Mycobacteriosis. The disease causes these symptoms:
- Ulceration on fins and skin
- Dropsy (body swelling and nodules on their internal organs)
There is not treatment for this disease, as it’s usually connected to poor care of the fish. The outbreak usually results in the loss of the colony – so if you notice any of these symptoms, remove the fish to a hospital tank. Make sure you keep the water parameters where they need to be and quarantine any new fish before adding them into your aquarium – whatever species they are.
|Best Antibiotics:||Nothing of note.|
|Treatments to Avoid:||Nothing of note.|
|Food Recommendations When Sick:||Make sure they get a thorough blend of protein-rich foods with their flakes and add in vegetables if they’re not already getting them.|
|Hospital Tank or Isolation Withing the Community Tank:||Always isolate any ill fish to prevent the potential loss of the shoal.|
5 Facts About Zebra Danios
- The zebra danio is named for the five uniform blue stripes on the fish’s sides.
- These little fish have become super popular with aquarists because of their playful personalities, as well as their easy breeding, availability, affordability, and of course, their good looks.
- Zebra danios have the ability to regrow their skin, fins, heart, and even their brains in the larval stages. They can also regenerate photoreceptors and retinal neurons after an injury.
- This species is one of the few species that has been flown into outer space.
- Zebra danios below to the largest fish family, which has over 2,000 species.